By common consent, President (Professor?) Obama's performance in last night's debate in Denver was lame and lacklustre. Where were his "zingers"? Why didn't he interject and interrupt to push back against Mitt Romney's omissions, exaggerations and half-truths?

It could have been so different. Here are 10 questions that Obama could have thrown at his Republican opponent at various moments during the 90-minute debate.

1) Governor Romney, you just said we've had "trillion-dollar deficits for the last four years" but I inherited a $1.3 trillion deficit from my Republican predecessor, George W. Bush. Correct me if I'm wrong, but didn't you vote and campaign for him in both 2000 and 2004?

2) Governor Romney, you just said "we ought to provide tax relief to people in the middle class" - would you like to share with the audience tonight how much tax relief you've provided yourself? Didn't you put your money in a Swiss bank account, and in the Cayman Islands, to avoid paying full US taxes?

3) Governor Romney, you said "high-income people are doing just fine in this economy" - indeed they are. How are YOU doing? Your late great father George released a dozen years of tax returns - why won't you follow his example? What have you got to hide?

4) Governor Romney, you just said I'm "entitled" to my own house and my own plane, just out of interest: how many homes do you own?

5) Governor Romney, you just said you were "concerned about America" - why then did you write off "47%" of the American people at a private dinner in May, and say your job "is not to worry about those people"? Will you take this opportunity tonight to look into that camera and apologise to half of the American population?

6) Governor Romney, you just said you want to "crack down on China" - so why, when you were running Bain Capital and making millions in bonuses, did you outsource US jobs to China? And not just to China, but to India and Mexico too? Why?

7) Governor Romney, you just said there are "differences" between 'Obamacare' and what you did in Massachusetts - but Jonathan Gruber, the MIT professor who helped me design Obamacare and you design Romneycare has said they're both "very similar" and have "the same basic structure" - are you saying Professor Gruber is a liar, Governor Romney? Are you?

8) Governor Romney, you say that I've given a "blank cheque" to Wall Street. But isn't it true that Wall Street has donated more than $37 million to your campaign? Aren't the guys from JP Morgan running your fundraising team?

9) Governor Romney, you say you want more "great teachers" in our schools, but you also want to cut back the spending and the size of government - how do you reconcile those two aims?

10) Governor Romney, you just said "Spain spends 42% of their total economy on government" and that "we're now spending 42% of our economy on government" - but that's flat wrong. According to the nonpartisan Congressional Budget Office, we spend just 23% of our economy on government - will you withdraw your false claim? And will you also acknowledge that Europe's economies are suffering right now because of the exact same austerity measures that you want to implement here in America?

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